Three mountain lion kittens struck and killed on local highways

Contributed photo/National Park Service
The area surrounding the Liberty Canyon exit on Highway 101 is an ideal location for a wildlife crossing because it has natural habitat on both sides of the freeway and connects to vast areas of open space, officials say.

contributed photo/National Park Service
Captured here with a remote camera is the only lion documented to have successfully crossed Highway 101 during a decade-long National Park Service study.

Game Camera 2009

Three kittens were found struck and killed on local highways in recent weeks, calling attention to what researchers say is one of the biggest barriers to mountain lions' long-term survival in the Santa Monica Mountains.

Roads are a challenge not only because of cars that can hit the mountain lions but also because they isolate a population from others in the region, said Seth Riley, wildlife ecologist with the Santa Monica Mountains National Recreation Area. Isolation can increase rates of lions fights and reduce genetic diversity, said Riley, who has studied mountain lions in the Santa Monica Mountains for the past 12 years.

"If we want to keep mountain lions in the Santa Monica Mountains, we need a better system of wildlife crossings," he said.

A safe crossing near the Liberty Canyon exit on Highway 101 in Agoura Hills would be key, according to the park service, and several agencies are working together to study such a crossing. This month, the Santa Monica Mountains Conservancy board will vote on whether to approve $200,000 to help fund a study, a first step to getting such a project approved.

Caltrans is being good about moving the ball forward, said Paul Edelman, the conservancy's deputy director of natural resources and planning. "The momentum is really phenomenal," he said.

In late January, three kittens were killed in two incidents. On Jan. 20, a mountain lion believed to be a few months old was killed on Kanan Dume Road in Malibu. On Jan. 31, two kittens, about 10 months old, were killed on Highway 126 in Los Angeles County, east of Piru.

Another mountain lion was killed in October. It was struck by a vehicle while crossing Highway 101 near Liberty Canyon overnight Oct. 6. It appears the animal successfully crossed the highway but then ran into a 10-foot-high wall on the other side.

Unable to get over the wall, it may have been trying to go back when it was hit.

Preliminary DNA results show the mountain lion was from outside the area, possibly from the San Gabriel Mountains or Los Padres National Forest. The kittens killed on Highway 126 were likely from Los Padres.

"We assume that there's a nice, big population of mountain lions there," Riley said. "That's the population that we're trying to stay connected to."

The Santa Monica Mountains population likely includes 10 to 15 adult lions, researchers say. For the local population to survive, males must come in from areas with higher levels of genetic diversity, researchers said.

Young mountain lions also need to expand into new territories. The biggest source of death among lions in the study is fights with other lions.

"No young male that we have been tracking has ever made it out from the Santa Monica Mountains," Riley said.

Caltrans spokesman Patrick Chandler said Tuesday that the agency is working with other groups on solutions. They include short-term projects such as removing or adding fencing or different vegetation and long-term proposals of adding a crossing over or under the highway.

"These are historic migration routes for wildlife," said Jim Hines, conservation chair for the Los Padres chapter of the Sierra Club. The local club and others support efforts to build such a wildlife crossing. The mountain lion population is an important part of the ecosystem, he said.

Mountain lion deaths

Jan. 31: Two kittens estimated to be 10 months old were killed on Highway 126 in northwest Los Angeles County.

Jan. 20: A kitten estimated to be a few months old was killed on Kanan Dume Road in Malibu.

Oct. 6, 2013: A mountain lion was struck and killed by a vehicle while crossing Highway 101 near Liberty Canyon in the Agoura Hills area.

During the past 12 years, the National Park Service knows of 13 mountain lions in the region being struck and killed by vehicles. Of those, two were radio-tracked as part of a study by the Santa Monica Mountains National Recreation Area.

The leading cause of death in the mountain lion study is fights with other mountain lions. Roads and highways that hem in the isolated population likely contribute to those conflicts.